The invention relates generally to devices for controlling EGR valves and turbochargers and more specifically to an integrated unit having an electric motor and electronic controller disposed in a housing and having a moving output member capable of positioning a control device in an exhaust gas recirculation (EGR) valve, a turbocharger or similar component.
Positioning of control devices in ancillary internal combustion engine components such as EGR valves and turbochargers may be accomplished by many classes and types of actuators. A frequently utilized actuator for EGR valves in passenger vehicles is a vacuum actuator driven by manifold vacuum. While the magnitude of the manifold vacuum provides a reasonably accurate driving signal to the EGR valve which opens or closes in proportion thereto, this system today may be characterized as primitive. Once the operating parameters such as endpoints and gain are established, the operational characteristics of the EGR valve are essentially fixed. They cannot accommodate, for example, other infrequently encountered operating conditions which might require a unique response.
A second consideration which encourages simplicity of operator design is the operating environment. Not only are such actuators disposed in the engine compartment and exposed to high operating temperatures but also they are mounted on or near the exhaust manifold which further raises operating temperatures.
Furthermore, the vacuum actuator is sized to provide reasonable operating force. However, the operating environment of EGR valves is such that they are susceptible to accumulation of carbon deposits which may significantly increase operating force. Large deposits generally render them inoperable. Given such simple mechanical operators, there has typically been no way to free the valve and there existed no feedback or signal to any associated device indicating the inoperable state.
A similar situation exists with regard to control devices associated with turbochargers. Once again, the operating environment of turbochargers, situated as they are in communication with the exhaust gases of the engine, are inhospitable. Accordingly then, controls for such devices are often simplified to improve reliability. Such simplification, however, compromises performance.
Another problem which also relates to the operating environment involves the interconnections between sensors, a controller and the actuator. The electric drive motor of the actuator may be mounted adjacent, for example, a throttle body fuel injection device and coupled to the control member by a linkage. Sensors provide information through cables and connectors to a remotely mounted controller which provides a drive signal to the electric motor, again through cables and connectors. The separation of these components and their interconnection through cables and connectors, may be the source of operating anomalies and failures.
The invention herein disclosed and claimed addresses these and many other design issues.
An integrated controller for EGR valves, turbochargers and the like includes an electric motor and controller in a common housing. The motor includes an output shaft having a segmented wheel and adjacent sensor which provide signals regarding the rotation and direction of rotation of the motor. The motor also drives a gear train having an output member which is coupled to and moves a control member such as a valve member in an EGR valve or turbocharger wastegate. A position coding feature is disposed on the output member and adjacent sensors provide signals regarding the position of the output member. The sensors drive a microcontroller which in turn drives the motor. The microcontroller also receives position commands or instructions from an external source. Preferably, the sensors, the drive motor, the gear train and the microcontroller are all disposed in a common housing.
It is thus an object of the present invention to provide an integrated motor and electronic controller which senses and positions a control member.
It is a further object of the present invention to provide a motor and electronic controller which are contained within a common housing.
It is a still further object of the present invention to provide a motor and controller which reduces the number of external wiring harnesses and electrical connectors relative to previous designs.
It is a still further object of the present invention to provide a motor and controller having sensing assemblies associated with both the motor and gear train outputs.
Further objects and advantages of the present invention will become apparent by reference to the following description of the preferred embodiment and appended drawings wherein like reference numbers refer to the same component, element or feature.